Question

What is the solution to the system of equations?

3x – 9y = -13
x – 3y = -7
(a) Use the substitution method to justify that the given system of equations has no solution.
(b) What do you know about the two lines in this system of equations?
PLEASE PLEASE PLEASE HELPPP

Answer 1

a. it has no solution

b. you can only substitute by making either the 'x' or 'y' the subject of either of the two equations.

Explanation:

3x - 9y = -13.............. eqn 1

x - 3y = -7................... eqn 2

from eqn 2

x - 3y = -7, substitute by making 'x' the subject

x = -7 + 3y.................. eqn 3

put eqn 3 into eqn 1

3x - 9y = -13

3( -7 + 3y) - 9y = -13

-21 + 9y - 9y = -13

9y - 9y = -13 + 21

0 = 8, which is not possible.